This invention relates to circular knitting machines and, more particularly, to an improved yarn feed system capable of presenting one or more of a plurality of yarns for selected utilization at each of a plurality of yarn feed locations.
Circular weft knitting machines of the general type herein of interest are both old and well-known in the art. The basic precepts determinative of the circular weft knitting operation extend back over 70 years and the intervening period has been characterized by a progression of generally relatively minor and essentially unitary component improvements. One area of such improvements is the manner in which one or more yarns may be selected from a plurality of available yarns and delivered to the appropriate feed station at the correct time. The specification and drawings of the aforesaid U.S. Pat. No. 4,796,444 are hereby incorporated in the filed present case by reference and in their entirety.
The present invention is directed to a novel and improved yarn feed system employing yarn selecting, directing, inserting and cutting elements to provide for more selective utilization and incorporation of one or more yarns into the product being fabricated, in response to preprogrammed control, from an available reservoir of a plurality of yarns at each operating sector.
More specifically, the present invention is directed to a yarn feed assembly for circular weft knitting machines in which a displaceable yarn supply includes a sector member and plurality of clamping devices that cooperate to tautly position the free ends of a plurality of yarns in spaced apart relation. The yarns extend from a reservoir through the movable sector member and into one of the clamping devices that keeps the yarns taut as they await selection and movement to a yarn feed location. A slotted guide is disposed at the yarn feed location as defined by the path of knitting needle displacement. The sector member is movable to position a single selected yarn at a pickup position. At the pickup position, a rotatable transfer arm engages the selected yarn and transports it into operative engagement with the slotted guide.
It is therefore an object of the present invention to provide an improved yarn feed system.
It is another object of the present invention to provide a yarn feed system of the type described which presents a plurality of yarns for selected utilization at a yarn feed location.
Yet another object of the present invention is to provide a yarn feed system of the type described including means for monitoring yarn consumption and effecting adjustments in actual stitch length and in response thereto.
To the above ends, other objects and advantages of the subject invention will be pointed out herein or will become apparent to those skilled in this art from the following portions of this specification and from the appended drawings which set forth, pursuant to the mandate of the patent statutes, the general structure and mode of operation of a circular weft knitting machine incorporating the principles of this invention and presently deemed to be the best mode for carrying out such invention. In conjunction therewith, it should be specifically noted that while the hereinafter described embodiment is particularly directed to a circular weft knitting machine adapted for sock fabrication, the principles of this invention are equally applicable to larger diameter knitting machines for general knit fabrics production and also to knitting machines for ladies hosiery and like articles.